Protein S-glutathionylation and vascular dysfunction with aging

项目总结 血管内皮功能障碍(VED)是老年人易患血管老化的一个重要特征 成人对心血管疾病的治疗。持续的氧化应激是VED的主要驱动力，其机制是协同失调 血管扩张剂NO和血管收缩因子内皮素-1(ET-1)的产生。但潜在的氧化还原机制是 主要原因不清楚。考虑到无效的-氧化应激，逆转氧化应激的新方法尤其引人注目 针对极其短暂的ROS的一般抗氧化疗法的Ness。蛋白质S-谷胱甘肽基化 SG)，一种稳定但可逆的氧化剂诱导的翻译后修饰主导着分子机制 用于氧化还原信号。在氧化还原过程中，谷氧还蛋白特异性地催化了PRS-SG的逆转 细胞功能的调节。谷氧还蛋白-1(Glrx-1)的功能障碍，它是脱谷胱甘肽的主要参与者 与心脏和大脑老化有关。它在血管老化中的作用尚不清楚。此应用程序构建在强大的 前提。我们已发表的和初步的研究表明，Glrx1缺乏和PRS-SG诱导促进 内皮功能障碍和衰老相关的代谢综合征以及在衰老过程中，主动脉Glrx1 随内皮细胞内PRS-SG升高而降低。文献中的证据也支持一种因果关系 Pr-SSG在VED中的作用S谷胱甘肽能解偶联eNOS，激活p21Ras，这是已知的 损害NO的生物利用度，刺激ERK1/2依赖的ET-1的表达。因此，我们假设与年龄有关的 Glrx1下调通过失调eNOS和ET-1的整合氧化还原信号促进VED，其中 可通过补充内皮细胞中的Grlx1逆转。这一中心假设是通过追求两个具体的 目的：1)了解Glrx1/PRS-SG与增龄性VED发生发展的关系。 使用C57BL6J小鼠，一个具有良好特征的衰老模型，我们将测量主动脉Glrx1的时间变化， 在幼年、中年和老年小鼠的血管内皮依赖性血管松弛和纵向 无创光学相干层析成像技术检测活体股动脉血流介导的扩张变化 技术。为了测试Glrx1下调在VED中的因果作用，我们将测试VED是否在 Glrx1基因敲除小鼠；2)测试一个新的概念，即在内皮细胞中补充Glrx1可以逆转衰老中的VED。 利用一种新的可诱导的内皮特异性Glrx1转基因小鼠模型，我们将确定其对VED的影响 青壮年Glrx1转基因表达中eNOS和ET-1的整合信号 老鼠。R21授权的积极结果将有助于我们进一步理解氧化还原信号是如何调节的 衰老对血管内皮细胞的多方面影响，促进VED，并提供新的抗氧化治疗策略 恢复老年人的血管功能。

PROJECT SUMMARY Vascular endothelial dysfunction (VED) is a key feature of vascular aging underlying the predisposition of old adults to CVD. Sustained oxidative stress is a major driving force for VED by synergically dysregulating the production of vasodilator NO and vasoconstrictor endothelin-1(ET-1). But the underlying redox mechanisms re- main unclear. Novel approaches to reversing oxidative stress are particularly compelling given the ineffective- ness of general antioxidant therapies that targets extremely short-lived ROS. Protein S-glutathionylation (PrS- SG), a stable but reversible oxidant-induced posttranslational modification dominates the molecular mechanisms for redox signaling. Reversal of PrS-SG is catalyzed specifically by glutaredoxin which thereby is critical in redox regulation of cellular function. Dysfunction of glutaredoxin-1 (Glrx-1), a major actor in the de-glutathionylation is implicated in cardiac, and brain aging. Its role in vascular aging is unknown. This application is built upon a strong premise. Our published and preliminary studies indicate that Glrx1 deficiency and PrS-SG induction promote endothelial dysfunction and aging-associated metabolic syndromes and that during aging, aortic Glrx1 is decreased with a concomitant increase in endothelial PrS-SG. Evidence in the literature also supports a causal role of Pr-SSG in VED in that S-glutathionylation can uncouple eNOS and activate p21Ras, which are known to impair NO bioavailability and stimulate Erk1/2 dependent-ET-1 expression. We thus hypothesize that age-related Glrx1 downregulation promotes VED by dysregulating the integrated redox signaling of eNOS and ET-1, which can be reversed by replenishing Grlx1 in endothelium. This central hypothesis is tested by pursuing two specific aims: 1) To understand the relationship between Glrx1/PrS-SG and the onset and progression of VED with aging. Using C57BL6J mice, a well-characterized model of aging we will measure the temporal changes in aortic Glrx1, PrS-SG, and endothelium-dependent vasorelaxation in young, middle-aged and old mice, and longitudinal changes of flow-mediated dilation of femoral artery in vivo using a non-invasive Optical-Coherence-Tomography technique. To test the causal role of Glrx1 downregulation in VED, we will test whether VED is aggravated in Glrx1 knockout mice; 2) To test a new concept that replenishing Glrx1 in endothelium can reverse VED in aging. Using a novel inducible endothelial specific Glrx1 transgenic mouse model, we will determine the impact on VED and the integrated signaling of eNOS and ET-1 of Glrx1 transgene expression in young, middle-aged, and old mice. The positive results in the R21 grant will help advance our understanding how redox signaling mediates the multifaceted effects of aging on ECs, promoting VED, and offer a new antioxidant therapeutic strategy to restore vascular function in older adults.